Target Diagnostic Instrument-Based Controls Framework for the National Ignition Facility (NIF) Page: 3 of 5
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TARGET DIAGNOSTIC INSTRUMENT-BASED CONTROLS
FRAMEWORK FOR THE NATIONAL IGNITION FACILITY (NIF)*
R. T. Shelton#, D. W. O'Brien, J. H. Kamperschroer, J. R. Nelson
Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
The extreme physics of targets shocked by NIF's 192-
beam laser are observed by a diverse suite of diagnostics
including optical backscatter, time-integrated and gated
X-ray sensors, and laser velocity interferometry.
Diagnostics to diagnose fusion ignition implosion and
neutron emissions are being planned. Many diagnostics
will be developed by collaborators at other sites, but ad
hoc controls could lead to unreliable and costly
operations. An instrument-based controls (I-BC)
framework for both hardware and software facilitates
development and eases integration. Each complex
diagnostic typically uses an ensemble of electronic
instruments attached to sensors, digitizers, cameras, and
other devices. In the I-BC architecture each instrument is
interfaced to a low-cost Windows XP processor and Java
application. Each instrument is aggregated with others as
needed in the supervisory system to form an integrated
diagnostic. The Java framework provides data
management, control services and operator GUI
generation. I-BCs are reusable by replication and
reconfiguration for specific diagnostics in XML.
Advantages include minimal application code, easy
testing, and better reliability. Collaborators save costs by
assembling diagnostics with existing I-BCs. This paper
discusses target diagnostic instrumentation used on NIF
and presents the I-BC architecture and framework.
NIF TARGET DIAGNOSTICS
The physics requirements derived from NIF
experimental campaigns are leading to a wide variety of
target diagnostics along with differing diagnostic
configurations for each experiment. To better understand
the physics of energetics, laser-hohlraum interaction,
hydrodynamics, and materials equation of state, a number
of diagnostic capabilities are needed. Diagnostics have
some common and some unique control requirements.
Optical diagnostics observe backscattered light from
targets and provide insight into energy conversion and
measure shock velocity. X-ray diagnostics can be either
integrating to capture total energy or gated to capture a
snap-shot of the target while experiencing laser-driven
shock. Neutron imaging, neutron time-of-flight, and
spectroscopy diagnose ignition experiments. Table 1 lists
target diagnostics currently planned for NIF and Figure 1
shows optical and X-ray diagnostics on the chamber.
* This work performed under the auspices of the U.S. Department of Energy by
Lawrence Livermore National Laboratory under Contract DE-AC52-
Table 1.Target diagnostics planned for NIF experiments
Full Aperture Backscatter
Optical Near Backscatter Imager
VISAR Velocity Interferometer
Dante X-ray Power & Imager
Hard X-ray Spectrometer
X-ray Streaked Detector
X-Ray X-ray Gated Detectors
Static X-ray Imager
Hard X-ray Imager
Neutron Time-of-Flight & Yield
Neutrons Neutron Imaging
and Gamma Bang Time
Gammas Magnetic Recoil Spectroscopy
Y f E Static
er t # \ X-ray
Figure 1. Optical and X-ray target
deployed on the target chamber.
NIF CONTROL SYSTEM
The computer control system for NIF is comprised of
several segments that utilize appropriate technology for
implementation. The Industrial Control System (ICS)
controls utilities such as vacuum, cooling and gas. The
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Shelton, R. T.; O'Brien, D. W.; Kamperschroer, J. H. & Nelson, J. R. Target Diagnostic Instrument-Based Controls Framework for the National Ignition Facility (NIF), article, October 3, 2007; Livermore, California. (digital.library.unt.edu/ark:/67531/metadc893049/m1/3/: accessed January 16, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.